| In-House Assist Limited | Professional & scientific | 2017 |
| Inablink Consultants Ltd | Professional & scientific | 2021 |
| Inception Group Holdings Limited | Professional & scientific | 2017 |
| Incisive Dental Laboratory Ltd | Manufacturing | 2014 |
| Inclusion Health Devon CIC | Health & social care | 2023 |
| Inclusive Exeter CIC | Education | 2019 |
| Inclusive Pathways Education Ltd | Education | 2024 |
| Incus Latam Ltd | Professional & scientific | 2018 |
| Indalo International Global Logistics Limited | Transport & logistics | 2009 |
| Indalo International Limited | Administrative & support | 2003 |
| Independent Accountancy Services Limited | Professional & scientific | 1998 |
| Independent Components Distributors Limited | Wholesale & retail | 1995 |
| Independent GP LLP | | 2023 |
| Independent Handling and Driver Training Limited | Administrative & support | 2004 |
| Independent Living West Country Limited | Health & social care | 2018 |
| Indexicon Limited | Professional & scientific | 2026 |
| Indi Affinity Limited | Wholesale & retail | 2022 |
| Indi Bay Properties Limited | Real estate | 2022 |
| Indiana Developments LLP | | 2011 |
| Indibug Limited | Administrative & support | 2020 |
| Indie Recruitment Limited | Administrative & support | 2016 |
| Indigo Terra Ltd | Hospitality | 2026 |
| Indoors Project Ltd | Information & communication | 2020 |
| Indulgence Beauty Exeter Limited | Other services | 2022 |
| Indulgence Hair Exeter Limited | Other services | 2025 |
| Industrial Cleaning Services SW Limited | Administrative & support | 2009 |
| Industrial Pro Limited | Wholesale & retail | 2025 |
| Inexeter Limited | Other services | 2010 |
| Infernal Software Ltd | Information & communication | 2023 |
| INFIN8 LAM Ltd | Other services | 2023 |
| Infinity Drylining Ltd | Construction | 2023 |
| Infinity Mirror Group Ltd | Professional & scientific | 2025 |
| Infinity Property Services MK Ltd | Real estate | 2023 |
| Inflate Ltd | Manufacturing | 2025 |
| Infocus Charity | Hospitality | 2009 |
| Infosoteria Limited | Information & communication | 2020 |
| Infragreen 4 RE UK Limited | Financial services | 2020 |
| Infranetzero Ltd | Information & communication | 2024 |
| Inhabit Limited | Construction | 2014 |
| Initiative Partnership Ltd | Professional & scientific | 2022 |
| Initiis Ltd | Wholesale & retail | 2019 |
| Injury Armour Ltd | Health & social care | 2022 |
| Inkhazarddel Ltd | Transport & logistics | 2021 |
| Inky Fingers Workshop CIC | Manufacturing | 2024 |
| Inky Little Fingers Limited | Manufacturing | 2005 |
| Inky Sprat Limited | Information & communication | 2012 |
| Inmo Works Limited | Administrative & support | 2017 |
| Innano Ltd | Manufacturing | 2024 |
| Innate Education Service Ltd | Professional & scientific | 2024 |
| Inner Universe Ltd | Other services | 2025 |
| Innerzong Ltd | Information & communication | 2023 |
| Innocent Property Limited | Real estate | 2024 |
| INNOV8 Training and Development Ltd | Education | 2013 |
| Innovate Transform Limited | Information & communication | 2024 |
| Innovative GAS Products Limited | Manufacturing | 2003 |
| Inoodle Ltd | Hospitality | 2022 |
| Inox Capital Limited | Construction | 2010 |
| Inox Developments Limited | Construction | 2019 |
| Inox Holdings Limited | Financial services | 2019 |
| Inox Homes (Appledore) Limited | Construction | 2018 |
| Inox Management Limited | Professional & scientific | 2019 |
| Inox Property Group (WL) Limited | Real estate | 2013 |
| Inox Property Group Limited | Extraterritorial | 2012 |
| Inox Property Limited | Professional & scientific | 2008 |
| Insight Plumbing and Heating Limited | Construction | 2013 |
| Insight Wealth Management Limited | Professional & scientific | 2022 |
| Insilicode Limited | Professional & scientific | 2023 |
| Insite Projects Ltd | Construction | 2020 |
| Insitu Property Limited | Real estate | 2013 |
| Insolvency Lawyers' Association Limited | Other services | 1989 |
| Inspiras Ltd | Professional & scientific | 2003 |
| Inspire Plastering and Rendering Limited | Construction | 2019 |
| Inspired Dental Care Limited | Health & social care | 2015 |
| Inspired Living (SW) Limited | Health & social care | 2025 |
| Inspired Properties & Rentals Limited | Real estate | 2021 |
| Inspired Transport and Removals Ltd | Transport & logistics | 2022 |
| Inspo Media Ltd | Professional & scientific | 2013 |
| Instant Car Care Ltd | Wholesale & retail | 2025 |
| Instant MOT Ltd | Wholesale & retail | 2021 |
| Instinct AI Ltd | Education | 2014 |
| Institute of Domestic Violence, Religion & Migration (Idvrm) C.I.C. | Professional & scientific | 2025 |
| Instix Dairy Limited | Manufacturing | 2012 |
| Instrumental Music Services Limited | Education | 2003 |
| Intasoft Limited | Information & communication | 1986 |
| Integrate Care, Support, Health and Housing Limited | Professional & scientific | 2017 |
| Integrated Lifestyle and Wellbeing Ltd | Other services | 2010 |
| Integrated Veterinary Services Limited | Professional & scientific | 2011 |
| Integrity Publishing Ltd | Information & communication | 2015 |
| Integrity Records Limited | Arts & recreation | 1993 |
| Inteliqo Marketing Limited | Professional & scientific | 2022 |
| Intelligent AI Limited | Information & communication | 2020 |
| Intelligent Assessment Technologies Limited | Education | 1998 |
| Intelligent Financial Reporting Solutions Limited | Professional & scientific | 2008 |
| Inter Property Consultancy Limited | Administrative & support | 1994 |
| Interconserve Limited | Real estate | 1977 |
| Interdive 2016 Limited | Education | 2002 |
| Interim Blue Ltd | Information & communication | 2012 |
| Interior Project Installations Ltd | Construction | 2014 |
| International Development Evaluation Association | Professional & scientific | 2003 |
| International Mortgage Solutions (Middle East) Limited | Professional & scientific | 2016 |